Electric relay



Nov. 6, 1934. w. F. COTTER El AL 1,980,038

ELECTRIC RELAY Filed March 23, 1933 Figoln I Fig.4.

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ATTORNEY.

Patented Nov. 6, 1934 UNITED STATES PATENT OFEQ ELECTRIC RELAY poration of New Yorlx Application March 23, 1933, Serial No. 662,255

7 Claims.

Our invention pertains to improvements in re lays; and especially electric relays for insuring the safe and proper connection of a work circuit to a supply circuit.

One of the objects of this invention is to provide an electric relay for connection to an alternatingcurrent supply circuit in such a way that if the connection between the leads of the supply circult and the conductors of the work circuit is to reversed no damage to any of the device in the work circuit can result.

A further object of the invention is to provide an electric relay adapted to connect the loud speaker of a radio receiver to a source of operating current so that if the proper connections are made the receiver will function as desired, but on the other hand, if the connections should be reversed, the speaker will not operate and no mishap of any kind will ensue.

These and other objects and advantages are set forth in the ensuing description and the novel features are defined in the appended claims. However, the right is reserved to make any changes that do not depart from the principle of 25, the invention or exceed the scope of the terms in which the claims are expressed.

On the drawing:

Fig. 1 shows diagrammatically one form of relay according to this invention; and

3p Figs. 2, 3, 4 and 5 show separate modifications thereof.

The same numerals identify the same parts throughout.

The invention is especially adapted to the use of loud speakers connected to one side of a power line upon which modulated radio signals, such as detected audio-frequency oscillations, are impressed. A copending application titled Electric relay, Ser. No. 662,205 filed of even date here- 49 with shows a difierent form of such a device. In.

Fig. l, the numerals 1 and 2 indicate the opposite sides of a power line carrying alternating current, the low side 2 of the line having the usual ground 3, and the speaker being indicated at l. The speaker will have a field coil 5 connected to the conductor 1 and a volume control coil 6 adapted to be joined through movable and fixed contacts 7 and 8 respectively to the other side of Bil the line 2. The contacts 7 and 8 will be normally terminal has an adjustable connection 17 with 66 the coil 6. In operation the connections are properly made as indicated in Fig. 1. Then the efiect of the rectifier 10 is to cause current to flow by way of ground 3 and coil 6 to anode l1; and cur- .rent then travels from the anode 11 to the cathode l3 and through the voice coils 9 and 5. Then the movable contact is caused by the relay 9 to engage the fixed contact 8, so that current can pass through the low side of the line through the volume control coil 6 and the speaker, and any 3'5 radio signals impressed upon the line 2 will energize the speaker 4.

In practice the terminals of the coil 5 and of the condensers 15 and 16 will all be joined to one terminal of the usual connector plug adapted to so be inserted into the socket terminals of an ordinary electric outlet; the contact 8 will be united to the other terminal of such a plug; and the ground terminal of the winding 6 may be a clip suitable for engagement with a water or gas pipe. When the parts are joined as shown, the speaker will operate, but if the plug be accidentally reversed so that the contact 8 is united to the line 1 and the terminals of the plug attached to the coil 5 and condensers l5 and 16, to the line 2, then the result will be simply that not enough current will pass through the rectifier to actuate coil 9 and no damage to any parts will follow. Of course, the cathode 13 may be heated by a filament which may receive its current from the secondary of a transformer, the primary of which will be connected to the lead 1 at one end and to the movable contact '7 at the other. The reversal of this transformer will make no difference because the filament will receive proper current 10 in either case to heat the cathode.

In practice, reactor coils of special design will be inserted into the leads 1 and 2 between the ground point 3 and the point of connection of the terminal 8 with the lead 2, and radio signal oscillations will be impressed on the lead 2 between the terminal 8 and said coils, as set forth in our companion application for patent on a Program distribution system, Serial No. 662,252 filed of even date herewith.

and at the other end to a-conductor 23.

In Fig. 2 connections are similar, except that a half-wave rectifier 10' is employed. This rectifier contains no grid. When properly connected to the circuit the speaker will operate and if the connections are reversed, the speaker does not operate and no damage occurs.

Fig. 3 indicates the use of a half-wave rectifier 19 of the electrolytic type with the connections corresponding to those of Figs. 1 and-2, this rectifier being joined directly to the line wires 1 and 2.

Fig. 4 shows the same kind of rectifier as in Fig. 3 with the same connections except that'the rectifier is coupled. to the transmission line by a transformer 20, the primary of which will be in series with the winding 6.

In Fig. 3, the terminals of the rectifier must be connected to the lead 1 and the coil 6, and the fixed contact 8 to the lead 2. As before the contact 8 and the terminal of the rectifier for connection to the lead 1 will be united by a suitable cord to the two points of a suitable connector plug. If this plug is correctly inserted into an outlet, the speaker will operate. If the plug is reversed, no operation will take place. In Fig. 4 the terminal of the primary of the transformer 20 for connection with the lead 1 and the terminal 8 will likewise be united to the points of a connector plug, for the same purpose and result.

Fig. 5 shows another form of relay in which connections are substantially the same' as in Fig. 1, but with a filament 21 included for heating the cathode 13 in the rectifier 10. This filament is supplied from the secondary coil of a transformer 22 connected at one end to the movable contact 7 The field coil 5 and condensers 15 and 16 are likewise joined to the conductor 23 and when this conductor is united to the line 1 and the fixed contact 8 united to the line 2, the connections are properly made. The contact 8 may be joined to one point or prong of a connector plug and the' conductor 23 to the other; the winding 6 having a ground clip for attachment to a pipe or any other convenient line to earth. The ground clip, of course, will always be properly connected, but the plug attached to conductor 23 and contact 8 may sometimes be reversed by an uninformed person so that the terminal 8 is incorrectly joined to the wire 1, while the transformer 22, the coil 5 and condensers 15 and 16 are incorrectly joined to the wire 2. In that case there will be not enough current supplied by the rectifier to the coil 9 to work it, and no damage will occur.

In all the views shown herein, the connections of the rectifiers to the coil 6 and the lead 1 could be reversed, and the operation thereof would not be affected. But the terminal of the rectifier, other than the one united to the coil 6 and contact 8,must always be united to the wires 1 and 2 respectively.

The loud speaker 4 may be either magnetic or dynamic in any of the arrangements above described.

Having described the invention, what is claimed is: a

1. The combination of an alternating-current energizing circuit, a relay circuit, a diode rectifier having an anode and cathode in the relay circuit, the anode being adapted to be connected to one side of the energizing circuit and the cathode to the opposite side, a relay coil in said relay circuit, a loud speaker field coil also in said relay circuit, a grounded winding connected to said rectifier, and an adjustable connection between the speaker and said last-named winding.

2. The combination of an alternating-current energizing circuit, a relay circuit, a half-wave electrolytic rectifier in the relay circuit and directly connected in the energizing circuit, a relay coil in said relay circuit, a loud speaker field coil also in said relay circuit, a grounded winding connected to said rectifier, and an adjustable connection between the speaker and said last-named winding.

3. The combination of an alternating-current energizing circuit, a relay circuit, a half-wave electrolytic rectifier in the relay circuit and coupled to the energizing circuit, a relay coil in said relay circuit, a loud speaker field coil also in said relay circuit, a grounded winding connected to said rectifier, and an adjustable connection between said speaker and said last-named winding.

4. The combination of an energizing circuit, a communication circuit between ground and one side of said energizing circuit, a loud speaker field winding, a relay coil, a rectifier connected to said energizing circuit and arranged to supply said field winding and relay coil with current, and means responsive to said relay coil for establishing and breaking said communication circuit.

5. The combination of an alternating current energizing circuit, a communication circuit be- 6. The combination of an energizing circuit, a

communication circuit between ground and one side of said energizing circuit, a loud speaker field winding, a relay for establishing and breaking said communication circuit, a rectifier connected to said energizing circuit and arranged tosupply said field winding and relay with current, and means for causing said rectifier to pass operating current only when a connection of predetermined polarity is established with said energizing circuit.

7. The combination of an alternating current 1 energizing circuit, a communication circuit between ground and one side of said energizing circuit, a loud speaker field winding, a relay for establishing and breaking said communication circuit, a rectifier connected to said energizing circuit and arranged to supply said field winding and relay with direct current, and means for causing said rectifier to pass operating current only when a connection of predetermined polarity is established with said energizing circuit.

' WILLIAM F. COTTER.

' MARION E. BOND. 

